Survivable Remote Site Telephony Configuration

A survivable remote site telephony (SRST) reference comprises the gateway that can provide limited Cisco CallManager functionality when all other Cisco CallManager servers for a device are unreachable. Typically assigned to device pools, SRST references determine the gateways where calling devices search when they attempt to complete a call if Cisco CallManager is unavailable. For more detailed information on SRST references, refer to the "Survivable Remote Site Telephony References" section in the Cisco CallManager System Guide.

Use the following topics to add, update, copy, or delete a SRST reference:

Finding an SRST Reference

Because you might have several SRST references in your network, Cisco CallManager lets you locate specific SRST references based on specific criteria. Use the following procedure to locate SRST references that are defined by a particular user.

Note During your work in a browser session, Cisco CallManager Administration retains your SRST reference search preferences. If you navigate to other menu items and return to this menu item, Cisco CallManager Administration retains your SRST reference search preferences until you modify your search or close the browser.

Procedure

Step 1 Choose System > SRST.

The Find and List SRST References window displays.

Step 2 From the drop-down list box, choose one of the following criteria:

•begins with

•contains

•ends with

•is exactly

Step 3 Specify the appropriate search text, if applicable, and click Find. You can also specify how many items per page to display.

Note To find all user-defined SRST references that are registered in the database, click Find without entering any search text.

A list of discovered SRST references displays by

•SRST Reference Name

•IP Address

•Port

Note You can delete multiple SRST references from the Find and List SRST References window by checking the check boxes next to the appropriate SRST references and clicking Delete Selected. You can choose all the SRST references in the window by checking the check box in the matching records title bar and clicking Delete Selected.

Step 4 From the list of records, click the SRST reference that matches your search criteria.

Note If devices are associated with this SRST reference, a message displays to tell you that devices need to be reset for the update to take effect. Cisco CallManager may drop calls in progress on an affected gateway may be dropped when the gateway is reset.

To reset the affected devices, click the Reset Devices button when the update is complete. If you do not want to reset the devices at this time, you can return to this item at any time and click the Reset Devices button to initiate the required device resets.

Deleting an SRST Reference

The following procedure describes how to delete an SRST reference.

Before You Begin

You cannot delete SRST references that device pools or other items are using. To find out which device pools are using the SRST reference, click the Dependency Records link from the SRST Reference Configuration window. If the dependency records are not enabled for the system, the dependency records summary window displays a message. For more information about dependency records, see the "Accessing Dependency Records" section on page A-3. If you try to delete an SRST reference that is in use, Cisco CallManager displays an error message. Before deleting an SRST reference that is currently in use, you must perform either or both of the following tasks:

Caution Before initiating this action, check carefully to ensure that you are deleting the correct SRST reference. You cannot retrieve deleted SRST references. If an SRST reference is accidentally deleted, you must rebuild it.

Tip You can also delete an SRST reference by locating and displaying the SRST reference that you want to delete and clicking Delete.

SRST Reference Configuration Settings

Enter a name in the SRST Reference Name field. The name can comprise up to 50 alphanumeric characters and can contain any combination of spaces, periods (.), hyphens (-), and underscore characters (_). Ensure that each SRST reference name is unique.

Note Use concise and descriptive names for your SRST references.

IP Address

Enter the IP address of the gateway for devices in a device pool to use as an SRST reference.

Port

Enter the port number for this SRST reference. Default value specifies 2000.

Note Change this value only if it does not match the gateway port setting. This value and the gateway port setting must match.

Is SRST Secure?

After you verify that the SRST-enabled gateway contains a self-signed or certificate-authority issued certificate, check this check box.

After you configure the SRST and reset the gateway and dependent phones, the Cisco CTL Provider service authenticates to the Certificate Provider service on the SRST-enabled gateway. The Cisco CTL client retrieves the certificate from the SRST-enabled gateway and stores the certificate in the Cisco CallManager database.

Tip To remove the SRST certificate from the database and phone, uncheck this check box, click Update, and reset the dependent phones.

SRST Certificate Provider Port

This port monitors requests for the Certificate Provider service on the SRST-enabled gateway. Cisco CallManager uses this port to retrieve the certificate from the SRST-enabled gateway. The Cisco SRST Certificate Provider default port equals 2445.

After you configure this port on the SRST-enabled gateway, enter the port number in this field.

Tip You may need to configure a different port number if the port is currently used or if you use a firewall and you cannot use the port within the firewall.

Update SRST Certificate

Tip This button displays only for existing secure SRST references.

After you click this button, the Cisco CTL client replaces the existing SRST certificate that is stored in the Cisco CallManager database. After you reset the dependent phones, the TFTP server sends the cnf.xml file (with the new SRST certificate) to the phones.